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Thread: copper tubing going to pressure switch

  1. #1

    Default copper tubing going to pressure switch

    The pressure switch for our irrigation well is located about 10 feet from the well itself. There is a length of 5/16 copper tubing connecting the two. I just replaced the tubing after it was damaged by our otherwise wonderful backhoe guy. Now the cut out pressure on the tank seems to be about 40psi. (Unfortunately I don't know what it was before this happened as I just bought a pressure gauge.) Do I need to bleed air out of the line for the pressure switch to operate correctly? And if so, how?

    Thanks!
    --Carrie

  2. #2
    Well driller,pump repair. and septic installer Waterwelldude's Avatar
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    Just by changing the tube, it should not change the setting of the switch.

    Did it work ok before it was cut?

    If it has, you should be fine by just replacing it.
    The air should not affect it. If it is to far of a run, the switch may bounce. on and off, on and off. If it does this, the tube may need to be shortened, or move the switch close to the tank.

    The switch always works better when it is close to the tank.


    Travis
    "I shall never surrender or retreat" -Col. William Travis


  3. #3

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    It did work well before it was cut. I fooled around with it more this afternoon and by adjusting the pressure switch post I got it to cut out at 60psi. I was surprised at how much I needed to turn the nut in order to get that additional 20 psi. I guess I need to have it almost at the bottom of the post in order to get 80 psi. By the way, what is the most pressure I can hope to get?

    Thanks!
    -Carrie

  4. #4
    Test, Don't Guess! cacher_chick's Avatar
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    I don't suggest unnecessarily raising the pressure on any existing well pump system. It's obviously been working and raising the pressure puts undue stress on the entire system.

    Think of it as like taking an old lady's car who never drove over 30mph and suddenly you are pushing it to go 80mph. The long-term results are not often good.

  5. #5
    Well driller,pump repair. and septic installer Waterwelldude's Avatar
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    I would not go more than 60 or 65psi Most tanks are rated at around 75psi max. Much more than 60 to 65psi, may start some older faucets to dripping.

    On most well pressure switches (square D)the tall screw or the one in the middle will increase(screwed down) or decrease(unscrewed up) the cut in and cut out pressure at the same time. It is around 2psi for every full rotation of the adjusting screw or nut.



    Travis

    ( Good suggestion )
    I
    I
    I
    V

    I don't suggest unnecessarily raising the pressure on any existing well pump system. It's obviously been working and raising the pressure puts undue stress on the entire system.

    Think of it as like taking an old lady's car who never drove over 30mph and suddenly you are pushing it to go 80mph. The long-term results are not often good.
    Last edited by Waterwelldude; 04-20-2009 at 07:28 PM.
    "I shall never surrender or retreat" -Col. William Travis


  6. #6
    That's all folks! Gary Slusser's Avatar
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    And when changing the pressure switch, you need to adjust the captive air pressure in a bladder tank before doing so. It needs to be done with no water in the tank and you set it to 1-2 psi BELOW the cutin (turn teh pump on) switch setting. I.E. 30/50 psi water pressure settings gets 29-28 psi air pressure with no water in the tank.

    I had an error above, thanks Travis.
    Last edited by Gary Slusser; 04-20-2009 at 09:21 PM.
    Gary Slusser Retired (= out of business)
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  7. #7

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    Thanks for all the replies! This well is for irrigation only, so I'm not worried about indoor faucets, etc. What I need is enough pressure to run a sprinkler system for our small bit of lawn. My husband says this is 80 psi. While yes, it was working before the tubing was cut, it wasn't working optimally. I'm not sure the tank was completely filling, and it wasn't giving enough pressure. What I'm trying to do now is optimize the system and make sure it is at very least working correctly. The tank says that the max pressure is 120psi. I definitely won't get anywhere near that, but I would love to get 80 or so.

    I'll put the small post nut at it's previous position and adjust the large post.

    Also, the tank is brand new last year, so I suppose there'd be more stress on the pump and pressure switch, but not the tank. The whole system wasn't used for about 10 years or so, maybe more and I'm very pleased to be able to use it at all.

    Thanks again.
    --Carrie
    Last edited by lahondamama; 04-21-2009 at 09:49 AM.

  8. #8
    That's all folks! Gary Slusser's Avatar
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    You have to have the air pressure set correctly in the pressure tank or you don't get good pressure when the pump isn't running.

    Eighty psi may not be possible if the pump can't get that high.

    The 125 lbs is the max operating psi of the tank, not that you should go over 80 psi. and 80 psi ma not be good for your plumbing or pump.
    Gary Slusser Retired (= out of business)
    Click Here to learn how to correctly size or program a water softener.
    CAUTION, as of Nov 12 2013 all YouTube videos showing how to rebuild a Clack valve have an error in them that can cause damage.

  9. #9

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    Quote Originally Posted by Gary Slusser View Post
    And when changing the pressure switch, you need to adjust the captive air pressure in a bladder tank before doing so. It needs to be done with no water in the tank and you set it to 1-2 psi BELOW the cutin (turn teh pump on) switch setting. I.E. 30/50 psi water pressure settings gets 29-28 psi air pressure with no water in the tank.

    I had an error above, thanks Travis.
    I just recently raised my pressure from 40/60 using just the middle screw (move the window) to a cut out pressure of ~70psi b/c I enjoy the pressure in the shower and it's quicker to fill a large tub. The house is 15 y/o and when it was built / inspected I'm pretty sure the inspector placed a static load of 100psi on it for a 12 hour period. I'm sure things change with age, but shouldn't the system continue to be able to withstand the 70psi?

    I have not yet adjusted the pressure in the bladder tank. I have a couple of questions about it.

    • What's the downside of not adjusting it?
    • When you mention that the tank must be 'empty', is having zero pressure in the pipes the same thing? Or must I drain the pipes?


    TIA,

    F

  10. #10
    That's all folks! Gary Slusser's Avatar
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    Raising the pressure decreases the number of gallons the tank can hold/deliver before the pumps comes on again, which won't provide proper cooling time for the motor in many cases, which is the primary cause of pump failure. Not setting the air pressure in the pressure tank correctly is the primary cause of 'bladder' type tank failures; especially when the water pressure has been increased without increasing the air pressure.

    To me, "empty" means devoid of, containing none etc. etc.. If you have zero psi on the pressure gauge and yet the tank and water lines above its elevation are full of water, you can not get the proper volume of air into the tank. So the air pressure says you got it right but the volume is wrong so eventually the bladder is stretched more than it is supposed to be. That incorrect air is the primary cause of bladder failures.

    The water in the pipes weighs .433 lbs per foot of elevation. One story is referred to as 10', and that would rob 10*.433= 4.33 psi from the proper air pressure per story up to the highest fixture in the house.

    You get one chance to do the right thing the first time and it usually takes longer to something right than not.... if you've already screwed things up, that usually costs much more time, effort and money than taking the time to do whatever right the first time. You are seriously short cycling your pump motor and over extending/stretching the tank's bladder. Which has shortened the life of the pump and tank.

    High pressure also can easily cause high velocity corrosion damage to copper tubing; if it is 8ft/sec or above.

    If it were me, 30/50 with 29-28 psi air pressure after draining the tank. And at that time I'd flush it too.

    All that to be able to powerwash yer butt....
    Gary Slusser Retired (= out of business)
    Click Here to learn how to correctly size or program a water softener.
    CAUTION, as of Nov 12 2013 all YouTube videos showing how to rebuild a Clack valve have an error in them that can cause damage.

  11. #11

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    Hi Gary,

    Thanks for all the information. I want to respond to some of your points, not to argue as you're the pro, but just to help me understand, etc. Also, I'm going to lower the pressure back to 40/60 mostly b/c I'm cheap and don't want the rest of the household using so much hot water! I have two daughters that will soon be entering their teen years, and I figure they could probably double my electric / oil bills...

    I'll place my comments inline in the color RED.

    Raising the pressure decreases the number of gallons the tank can hold/deliver before the pumps comes on again (strictly because of the increased flow rate I assume), which won't provide proper cooling time for the motor in many cases (I think I'm safe from overheating based on the conjunction of two points; 1 - We don't use all that much water as we don't use our well water for irrigation or washing cars, 2 - The motor/pump is 265' below grade submerged in a constant ~50F water. That has to keep it pretty cool I would think), which is the primary cause of pump failure. Not setting the air pressure in the pressure tank correctly is the primary cause of 'bladder' type tank failures; especially when the water pressure has been increased without increasing the air pressure.

    If it were me, 30/50 with 29-28 psi air pressure after draining the tank. And at that time I'd flush it too. (Yeah, I'll do the right thing and lower my pressure...)

    All that to be able to powerwash yer butt.... (but(t), my god, it feels so good!!! )

  12. #12
    That's all folks! Gary Slusser's Avatar
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    Your motor will raise the 50f around it fairly quickly because usually, the water above the pump is what is being used and the motor is below the pump inlet.

    Yeah, I know it feels good but I didn't want the 4 daughters to learn that before leaving home where I paid the bills.
    Gary Slusser Retired (= out of business)
    Click Here to learn how to correctly size or program a water softener.
    CAUTION, as of Nov 12 2013 all YouTube videos showing how to rebuild a Clack valve have an error in them that can cause damage.

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